Diagnostic performance of a stepwise cytological algorithm for biliary malignancy in primary sclerosing cholangitis

Area of Science:

• Hepatology and Gastroenterology
• Oncology
• Diagnostic Cytopathology

Background:

• Early detection of cholangiocarcinoma (CCA) in patients with primary sclerosing cholangitis (PSC) presents significant diagnostic challenges.
• PSC is a risk factor for developing CCA, necessitating accurate and timely diagnostic methods.

Purpose of the Study:

• To evaluate the diagnostic accuracy of a combined approach using biliary brush cytology and fluorescence in-situ hybridization (FISH) for detecting biliary malignancy in PSC patients.
• To assess the effectiveness of a stepwise diagnostic algorithm incorporating FISH for equivocal cytology results.

Main Methods:

• A retrospective study of 208 PSC patients who underwent biliary brushings between 2009 and 2015.
• Cytology samples were classified as benign, equivocal, or malignant, with equivocal cases further analyzed by FISH.
• Diagnosis of CCA was confirmed through 12-month follow-up.

Main Results:

• The stepwise diagnostic algorithm achieved a sensitivity of 80% and specificity of 96% for CCA detection.
• In patients with equivocal cytology, the sensitivity for CCA diagnosis increased to 100% with the addition of FISH.
• Overall diagnostic accuracy for CCA detection in the PSC cohort was 95%.

Conclusions:

• Biliary brush cytology combined with sequential FISH analysis in equivocal cases is a highly predictive diagnostic strategy for CCA in PSC.
• This approach supports the utility of FISH as a crucial tool for confirming biliary malignancy when cytology results are inconclusive in PSC patients.